Shinji Takai (1), Denan Jin (1), Kazuyoshi Kirimura (2), Junko Ikeda
(2), Masato Sakaguchi (1), Kimiye Baba (3), Tadashi Fujita (2) and Mizuo
(1) Department of Pharmacology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
(2) Department of Hygienic Chemistry and (3) Department of Pharmacognosy, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka 569-1041, Japan
Abstract: We investigated whether a lipoxygenase inhibitor, panaxynol, affected the vascular contraction induced by angiotensin (Ang) II and the mean arterial pressure in spontaneously hypertensive rats (SHR). Panaxynol suppressed dose-dependently the contractile responses induced by 30 nM Ang II in isolated intact and endothelial cell-denuded aorta in the hamster. IC50 values in the intact and endothelial cell-denuded aorta were 23 and 20 microM, respectively. In SHR, the mean arterial pressure after injection of 30 and 60 mg/kg panaxynol was reduced, and the maximum hypotensive values were 23 and 48 mmHg, respectively. Thus, lipoxygenase products may affect the renin-angiotensin system.
Keywords: Lipoxygenase, Angiotensin II, Contraction